Methods of promoting adhesion between transfer molded IC packages and injection molded plastics for creating over-molded memory cards

ABSTRACT

A flash memory card and methods of manufacturing same are disclosed. The card includes a semiconductor package fabricated to receive a single-sided or double-sided lid. A surface of the semiconductor package may be formed with holes, trenches and/or pockmarks. After the holes, trenches and/or pockmarks are formed, a lid may be attached to the package surface in an injection molding process. During the injection molding process, the molten plastic flows into the holes, trenches and/or pockmarks to interconnect with the surface of the semiconductor package. Thus, when the molten plastic hardens, the holes, trenches and/or pockmarks ensure that the lid remains firmly attached to semiconductor package.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention relate to methods of manufacturinga semiconductor package.

2. Description of the Related Art

The strong growth in demand for portable consumer electronics is drivingthe need for high-capacity storage devices. Non-volatile semiconductormemory devices, such as flash memory storage cards, are becoming widelyused to meet the ever-growing demands on digital information storage andexchange. Their portability, versatility and rugged design, along withtheir high reliability and large capacity, have made such memory devicesideal for use in a wide variety of electronic devices, including forexample digital cameras, digital music players, video game consoles,PDAs and cellular telephones.

While a wide variety of packaging configurations are known, flash memorystorage cards may in general be fabricated as system-in-a-package (SiP)or multichip modules (MCM), where a plurality of die are mounted on asubstrate. The substrate may in general include a rigid base having aconductive layer etched on one or both sides. Electrical connections areformed between the die and the conductive layer(s), and the conductivelayer(s) provide an electric lead structure for integration of the dieinto an electronic system. Once electrical connections between the dieand substrate are made, the assembly is then typically encased in amolding compound in a transfer molding process to provide a protectivepackage.

In view of the small form factor requirements, as well as the fact thatflash memory cards need to be removable and not permanently attached toa printed circuit board, such cards are often built of a land grid array(LGA) package. In an LGA package, the semiconductor die are electricallyconnected to exposed contact fingers formed on a lower surface of thepackage. External electrical connection with other electronic componentson a host printed circuit board (PCB) is accomplished by bringing thecontact fingers into pressure contact with complementary electrical padson the PCB. LGA packages are ideal for flash memory cards in that theyhave a smaller profile and lower inductance than pin grid array (PGA)and ball grid array (BGA) packages.

Semiconductor die are typically batch processed on a panel and thensingulated into individual packages upon completion of the fabricationprocess. Several methods are known for singulating the semiconductorpackages including, for example, sawing, water jet cutting, lasercutting, water guided laser cutting, dry media cutting and diamondcoated wire cutting.

Once singulated, fabrication of the flash memory card may be completedby encasing a semiconductor package within a pair of lids. The lidsprotect the package, as well as cover contacts pads, such as test padsthat are left exposed in the package through the molding to allow forelectrical test and burn-in after the package has been completed. It isalso known to provide only a single lid, on one side of the package, toprotect the package and cover exposed contact pads.

The one or two lids are typically affixed to the package in an injectionmolding process. One difficulty in affixing single-sided lids is thatthe single-sided lid formed in the injection molding process does notadhere well to the outer surface of the molding compound of the packageformed in the transfer molding process. One solution has been to form acard 20 as shown in prior art FIG. 1, including a semiconductor package22 and a lid 24 which partially wraps around the opposite side of thepackage. The wrap around configuration disadvantageously increases theoverall thickness of the finished semiconductor card.

SUMMARY OF THE INVENTION

Embodiments of the present invention relate in general to a flash memorycard including a semiconductor package fabricated to receive asingle-sided or double-sided lid, and methods of manufacturing same. Inone embodiment, after singulation of a semiconductor package from apanel of semiconductor packages, a plurality of holes may be formed inan upper surface of the semiconductor package and out of the side edgesof the semiconductor package. The holes may be formed through thepackage molding compound and do not interfere with the electricalfunction of the package. After the holes are formed, a lid may beattached to the package in an injection molding process. During theinjection molding process, the molten plastic flows into and through theholes. Thus, when the molten plastic hardens, the plastic-filled holesensure that the lid remains firmly attached to the semiconductorpackage.

In a further embodiment, the molding compound surface of thesemiconductor package may be scored with a laser so as to create rough,pock-marked areas on the surface of the package. When the lid isinjection molded onto the semiconductor package, the molten plastic willfill the pockmarks formed by the laser. The mating interconnection ofthe molten plastic with the pock-marked surface affixes the lid to thesemiconductor package.

In another embodiment of the present invention, a plurality of trenchesmay be formed in the surface of the semiconductor package. The trenchesmay be undercut so as to be wider at the bottom of the trench than atthe outer surface. Thus, during the injection molding process forattaching the lid, the molten plastic flows into the trenches with theundercuts serving to lock the lid to the semiconductor package uponhardening of the molten plastic. The trenches may be discretely formedshapes in the surface of the semiconductor packages, such as for examplesquares, rectangles or other shapes. Alternatively, the trenches may beformed in rows extending across the surface, or a portion of thesurface, of the semiconductor package.

In another embodiment of the present invention, instead of cutting intothe surface of the semiconductor package, a compound may be applied tothe surface of the semiconductor package which is capable of affixingthe lid to the semiconductor package. The compound may be a variety ofknown adhesives, such as for example an adhesive film, a glue or aheat-activated chemical adhesive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a conventional wrap-around lid for a flashmemory card.

FIG. 2 is a flowchart of the method of fabricating a flash memory cardaccording to embodiments of the present invention.

FIG. 3 is a top view of a portion of a panel of integrated circuitsduring the fabrication process according to the present invention.

FIG. 4 is a cross-sectional view through line 4-4 in FIG. 3.

FIG. 5 is a top view of a panel of molded integrated circuits accordingto embodiments of the present invention prior to being cut intoindividual integrated circuit packages.

FIG. 6 is a perspective view of a semiconductor package including holesfor receiving molten plastic during the injection molding process foraffixing a lid onto the semiconductor package.

FIG. 7 is a cross-sectional view of the package shown FIG. 6.

FIGS. 7A through 7C are a further alternative embodiment including holesformed parallel to the surface of the semiconductor package.

FIG. 8 is a cross-sectional view similar to FIG. 7 and further showing alid affixed to the semiconductor package.

FIG. 9 is a perspective view of a semiconductor package includingtapered side edges and holes for affixing a lid onto the semiconductorpackage.

FIG. 10 is a cross-sectional view of the semiconductor package shown inFIG. 9.

FIG. 11 is a perspective view of a semiconductor package includingstepped edges and holes for affixing a cover onto the semiconductorpackage.

FIG. 12 is a cross-sectional view through the semiconductor package ofFIG. 11.

FIG. 13 is a top view of a semiconductor package scored with a laser toinclude rough, pock-marked sections.

FIG. 14 is a side view of the semiconductor package shown in FIG. 13.

FIG. 15 is a perspective view of a semiconductor package including aplurality of trenches for affixing a lid to the semiconductor package.

FIG. 16 is a cross-sectional view through line 16-16 in FIG. 15.

FIG. 17 is a cross-sectional view through line 17-17 in FIG. 15.

FIG. 18 is a perspective view of a semiconductor package including aplurality of rows of trenches for affixing a lid to the semiconductorpackage.

FIG. 19 is a cross-sectional view of the semiconductor package shown inFIG. 18.

FIG. 20 is a perspective view of a semiconductor package including alayer of compound applied to the semiconductor package for affixing alid to the semiconductor package.

FIG. 21 is a cross-sectional view of the semiconductor package of FIG.20 and further including a lid.

DETAILED DESCRIPTION

Embodiments of the invention will now be described with reference toFIGS. 2 through 21 which relate to a flash memory card including asemiconductor package fabricated to receive a single-sided ordouble-sided lid, and methods of manufacturing same. It is understoodthat the present invention may be embodied in many different forms andshould not be construed as being limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete and will fully convey the invention tothose skilled in the art. Indeed, the invention is intended to coveralternatives, modifications and equivalents of these embodiments, whichare included within the scope and spirit of the invention as defined bythe appended claims. Furthermore, in the following detailed descriptionof the present invention, numerous specific details are set forth inorder to provide a thorough understanding of the present invention.However, it will be clear to those of ordinary skill in the art that thepresent invention may be practiced without such specific details.

In general, semiconductor packages according to the present inventionare formed in a process described with respect to FIG. 1. Thefabrication process begins in step 50 with a panel 100, shown partiallyfor example in FIGS. 3 and 4. The type of panel 100 used in the presentinvention may for example be a leadframe, printed circuit board (“PCB”),a tape used in tape automated bonding (“TAB”) processes, or other knownsubstrates on which integrated circuits may be assembled andencapsulated.

In embodiments where panel 100 is a PCB, the substrate may be formed ofa core, having a top conductive layer formed on a top surface of thecore, and a bottom conductive layer formed on the bottom surface of thecore. The core may be formed of various dielectric materials such as forexample, polyimide laminates, epoxy resins including FR4 and FR5,bismaleimide triazine (BT), and the like. The conductive layers may beformed of copper or copper alloys, plated copper or plated copperalloys, Alloy 42 (42Fe/58Ni), copper plated steel, or other metals andmaterials known for use on substrates.

The metal layers of panel 100 may be etched with a conductance patternin a known process for communicating signals between one or moresemiconductor die and an external device (step 52). Once patterned, thesubstrate may be laminated with a solder mask in a step 54. Inembodiments where substrate 100 is used for example as an LGA package,one or more gold layers may be formed on portions of the bottomconductive layer in step 56 to define contact fingers on the bottomsurface of the semiconductor package as is known in the art forcommunication with external devices. The one or more gold layers may beapplied in a known electroplating process. It is understood that thesemiconductor package according to the present invention need not be anLGA package, and may be a variety of other packages in alternativeembodiments including for example BGA packages.

A plurality of discrete integrated circuits 102 may be formed on panel100 in a batch process to achieve economies of scale. The fabrication ofintegrated circuits 102 on panel 100 may include the steps 58 and 60 ofmounting one or more semiconductor die 104 and passive components 106 onpanel 100 for each integrated circuit 102.

The one or more semiconductor die 104 may be mounted in step 58 in aknown adhesive or eutectic die bond process, using a known die-attachcompound. The number and type of semiconductor die 104 are not criticalto the present invention and may vary greatly. In one embodiment, theone or more die 104 may include a flash memory array (e.g., NOR, NAND orother), S-RAM or DDT, and/or a controller chip such as an ASIC. Othersemiconductor die are contemplated. The one or more die 114 may beelectrically connected to panel 100 by wire bonds 108 in step 62 in aknown wire-bond process. The die may be stacked in an SiP arrangement,mounted side-by-side in an MCM arrangement, or affixed in anotherpackaging configuration.

Although not specifically called out on the flowchart of FIG. 1, variousvisual and automated inspections may be made during the above-describedfabrication of the plurality of integrated circuits 102 on panel 100.

Once the plurality of integrated circuits 102 have been formed on panel100, each of the integrated circuits 102 may be encapsulated with amolding compound 120 in step 64 and as shown in FIG. 5. As is known inthe art, molding compound 120 may include various compounds such asepoxy, hardener, silicon dioxide and other organic compounds, and may beavailable for example from Sumitomo Corp. and Nitto Denko Corp., bothhaving headquarters in Japan. Other molding compounds from othermanufacturers are contemplated. The molding compound may be appliedaccording to various processes, including by transfer molding, toencapsulate each of the integrated circuits 102. As shown in FIG. 5,contact fingers 122 may be left exposed.

In the transfer molding process, the panel 100 is placed in a mold andliquid molding compound is then flowed into the mold and around thepanel. After hardening sufficiently to be removed from the mold, theencapsulated panel may then be cured, for example in an oven at 175° for5 hours, to permanently set the molding compound. The curing process maybe performed under different temperature and time conditions inalternative embodiments.

Although shown with a generic rectangular shape in FIG. 5, the moldedintegrated circuits may have irregular and/or curvilinear shapes inembodiments. A method for forming irregular shaped semiconductorpackages is disclosed for example in U.S. patent application Ser. No.11/265,337, entitled “Method of Manufacturing Flash Memory Cards,” whichapplication is assigned to the owner of the present application andwhich application is incorporated by reference herein in its entirety.

After molding step 64, a marking can be applied to the molding compound120 in step 66. The marking may for example be a logo or otherinformation printed on the surface of the molding compound 120 for eachintegrated circuit 102. The marking may for example indicatemanufacturer and/or type of device. Marking step 66 may be omitted inalternative embodiments of the present invention.

Each of the integrated circuits 102 may next be singulated in step 68.Singulation step 68 involves cutting integrated circuits 102 on panel100 into a plurality of individual semiconductor packages. Known cuttingdevices include, for example, water jet cutting, laser cutting, waterguided laser cutting, dry media cutting, and diamond coated wirecutting. Water can also be used together with laser cutting to helpcomplement or focus its effects. As is known in the art, the abovecutting methods are able to achieve sophisticated rectilinear and/orcurvilinear shapes of the individualized integrated circuit packages. Afurther description of the cutting of integrated circuits from a paneland the shapes which may be achieved thereby is disclosed in U.S.Publication No. 2004/0259291, entitled, “Method For EfficientlyProducing Removable Peripheral Cards,” which application is incorporatedby reference herein in its entirety. It is understood that thesingulated integrated circuits may be formed by other processes thanthat described above in alternative embodiments.

As explained in the Background of the Invention section,injection-molded lids do not adhere well to transfer-molded epoxycompounds forming the outer surfaces of semiconductor packages.Therefore, in accordance with the present invention, a lid attachmentpreparation step 70 may be performed to form one or more features in asurface of the molding compound to prepare the semiconductor package tomore securely receive a lid which is affixed to one or two sides of thepackage.

A first embodiment of the lid attachment preparation step 70 is shown inthe perspective and cross-sectional views of FIGS. 6 and 7,respectively. After singulation of a semiconductor package 130 in step68, features in the form of a plurality of holes 132 may be formedobliquely down through a surface 134 of the semiconductor package andout of the side edges 136 of the semiconductor package as shown. Theholes 132 may be formed through the molding compound 120, and possiblythrough the package substrate, provided the holes do not interfere withelectrical circuit(s) defined on the substrate or the electricalfunction of the package 130.

In embodiments, the holes 132 may have a diameter of approximately 0.25millimeters, and be spaced apart from each other approximately onemillimeter. It is understood that the diameter of holes 132 may belarger or smaller than 0.25 millimeters, and the spacing between holes132 may be larger or smaller than one millimeter in alternativeembodiments of the present invention. The holes 132 may be formed inmolding compound 120 by various known processes such as, for example,with a mechanical drill or a laser. The holes may be formed around one,two, three or all four side edges of the semiconductor package 130.

The holes 132 may be formed at an angle of approximately 45°, but theangle may be more or less than 45° in alternative embodiments. In afurther alternative embodiment shown in FIGS. 7A through 7C, instead ofholes 132 being drilled at an angle through the top surface 134 and sideedges 136, the holes 132 may be drilled through the side edges 136parallel to the surface 134 of the semiconductor package 130 as shown inFIG. 7A. In such an embodiment, the holes 132 may be drilled between thesurface 134 and the opposed surface so as not to break through thesurface 134 or opposed surface. Alternatively, the drilled holes may beparallel to the surface 134, but break the surface 134 as shown in FIGS.7B and 7C. In the embodiments shown in FIGS. 7B and 7C, the longitudinalaxis of holes 132 are preferably below the surface 134 so that the holes132 have an arclength of greater than 180°. In the embodiments of FIGS.7A through 7C, the holes may be formed to a desired length within thepackage 130, such as, for example, one to four millimeters.

Holes 132 may be circular. In alternative embodiments, as opposed toholes 132 being circular, holes 132 may be slots may be formed throughthe surface 134 of package 130 and out of the side edges 136.Alternatively, the slots may be formed into the side edges 136 andparallel to the surface 134, as in the holes 132 of FIGS. 7A through 7C.

Referring again to the flowchart of FIG. 1 and the cross-sectional viewof FIG. 8, a semiconductor package 130 formed as described above mayfurther be enclosed within an external lid 138 in a step 72 to form afinished flash memory card 140. The lid 138 may provide an externalcovering for the semiconductor package and establish external productfeatures (for example including any notches, chamfers, etc. to aid inproper insertion of the card 140 in a host device). Lid 138 may beformed of various plastics as is known in the art, such as for example,polycarbonate, and may be affixed to package 130 in various processes asis known in the art, such as for example, injection molding.

In an injection molding process, the package 130 may be placed within amold, and then molten plastic may be flowed over surface 134 and sideedges 136 under high pressure and temperature. As seen in FIG. 8, duringthe injection molding process, the molten plastic flows into and throughholes 132. Thus, when the molten plastic hardens, the plastic-filledholes 132 ensure that lid 138 remains firmly attached to semiconductorpackage 130. As shown in FIG. 8, the lid 138 may be a single-sided lid,affixed to surface 134 and surrounding side edges 136, with theremaining package surface being uncovered. In further embodiments, thelid 138 may completely enclose all of the surfaces of the semiconductorpackage 130. In such embodiments, the lid may be formed of a singleunitary piece surrounding the package 130, or in two parts which areadhered to each other and which together enclose the semiconductorpackage 130.

As indicated above, the embodiment of the present invention shown inFIGS. 6 through 8 is one of many possible embodiments for enhancing theattachment of lid 138 to semiconductor package 130. FIGS. 9 through 12show further embodiments including holes 132 formed through asemiconductor package 130 which has tapered or stepped side edges.Further details of a semiconductor package having tapered or steppededges and a lid therefore are described in U.S. patent application Ser.No. 11/356,276, entitled “A SIP Module With a Single Sided Lid,” filedFeb. 15, 2006, which application is incorporated herein by reference inits entirety.

In particular, as shown in FIGS. 9 and 10, the semiconductor package 130may be formed with tapered edges 142. Holes 132 may be formed throughthe surface 134 of semiconductor package 130 and out of tapered edges142. The holes 132 may be as described above. In the embodiments shownin FIGS. 9 and 10, the semiconductor package is a trapezoid incross-section with the surface 134 having a greater width than itsopposed surface. In a further embodiment of the present invention (notshown), instead of being a trapezoid, the tapered edges 142 may beparallel to each other so that semiconductor package 130 forms aparallelogram in cross-section (i.e., the surface 134 has the same widthas its opposed surface). In a further embodiment shown in FIGS. 11 and12, semiconductor package 130 may alternatively include stepped edges144 including holes 132 as described above. In each of the embodimentsshown in FIGS. 9 through 12, the holes 132 and the tapered or steppededges together operate to securely affix lid 138 to semiconductorpackage 130.

Lid attachment preparation step 70 may form features on a surface of themolding compound other than holes through molding compound 120 infurther embodiments. For example, as shown in FIG. 13, the top surfaceof semiconductor package 130 may be scored with a laser so as to createrough, pock-marked areas 146 on the surface 136 of the package 130. Inparticular, a laser may be provided with a known frequency, intensityand focal point so that, when passed over the upper surface ofsemiconductor package 130, the laser burns into the surface 136 to adesired depth, for example 1 to 10 microns (though it may be more orless than that in alternative embodiments).

As indicated above, molding compound 120 is formed of a variety ofcompounds, including epoxy, hardener, silicon dioxide and other organiccompounds, each of which burns or melts at different temperatures. Whenthe molding compound is scored by the laser, the laser will burn awaysome of these compounds, such as, for example, the epoxy and organiccompounds, while leaving others of the compounds intact. The result isan uneven, rough, pock-marked area 146 as shown for example in FIG. 13.

When the lid 138 is injection molded onto semiconductor package 130, themolten plastic will fill the pockmarks formed by the laser as shown inFIG. 14. The mating interconnection of the molten plastic with eachpock-mark 148 affixes the lid 138 to the semiconductor package 130. Itis understood that the laser may score the surface of semiconductorpackage 130 in a variety of patterns to form pockmarks on surface 134 asdescribed above. In embodiments, the entire surface 134 of semiconductorpackage 130 may be scored with the laser.

In a further embodiment of the present invention shown in FIGS. 15through 17, the lid attachment preparation step 70 may comprise forminga plurality of trenches 150 in the surface 134 of semiconductor package130. In embodiments, one or more sidewalls of the trenches 150 may beundercut as shown so as to be wider at the bottom of the trench 150(i.e., distal from the surface 134) than at the surface 134. Thus, asseen in the cross-sectional views of FIGS. 16 and 17, during theinjection molding process, the molten plastic flows into trenches 150,with the undercuts serving to lock the lid to the semiconductor package130 upon hardening of the molten plastic.

In embodiments, the trenches may be rectangular in shape and may extendapproximately one millimeter down into the surface 134 of thesemiconductor package 130. It is understood that trenches 150 need notbe square in further embodiments, and may be for example rectangular,triangular, rounded or irregular shaped. Additionally, it is understoodthat the trenches 150 may extend greater than or less than onemillimeter down into the surface 134 of molding compound 120, with theprovision that the trenches 150 not interfere with the electricaloperation of the semiconductor package 130. The length and width oftrenches 150 within the surface 134 may vary in alternative embodiments.Where trenches 150 are substantially square, the length of a trench maybe for example between 1 millimeter and 10 millimeters, but it isunderstood that the length may be less than 1 millimeter and greaterthan 10 millimeters in alternative embodiments.

FIGS. 16 and 17 are cross-sectional views through lines 16-16 and 17-17on FIG. 15, respectively. As indicated by FIGS. 16 and 17, all foursides of each trench 150 may be undercut as described above. In furtherembodiments of the present invention, it is understood that one or moresides or portions of a trench 150 may include no undercut, but insteadmay be a vertical cut or an oppositely inclined cut than the undercutportions of a trench 150.

Undercut trenches 150 may be formed by mounting semiconductor package130 on a platform of known design. The platform may be controllablytilted at angles about two axes of freedom relative to a cutting laserso as to allow the laser to form the trenches 150 having undercut edgesaround the periphery of the trench. The intensity, frequency and focalpoint of the laser may be selected to dig trenches 150 to the desireddepth and configuration within the semiconductor package 130. It isunderstood that other mechanisms may be used to form trenches 150 havingundercut edges as described above. As a further example, trenches 150may be mechanically cut using, for example, a diamond cutting blade or agrinding wheel to form trenches 150 with the desired undercut edges. Itis also contemplated that the trenches 150 may be chemically etched.

In the embodiment of FIGS. 15 through 17, trenches 150 are formed asdiscrete squares or other shapes in the surface 134 of semiconductorpackage 130. In a further embodiment of the present invention shown inFIGS. 18 and 19, the trenches may instead be formed as rows 152 acrossthe surface 134 of semiconductor package 130. The rows of trenches 152may be formed in the same manner and configuration as trenches 150, withthe exception that they extend across all or a portion of the length orwidth of the surface 134 of semiconductor package 130. Row trenches 152may be parallel to each other and may be parallel to respective edges ofsemiconductor package 130. In a further embodiment, rows 152 need not beparallel to edges of semiconductor package 130 nor to each other. Insuch embodiments, the rows 152 may randomly cross each other, or may beprovided in a cross-hatched pattern in surface 134.

In a still further embodiment of the present invention, instead ofcutting into the surface 134 of semiconductor package 130, a compoundmay be applied to the surface of semiconductor package 130 capable ofaffixing the lid 138 to semiconductor package 130. For example, as shownin FIG. 20, a compound 160 may be applied to the surface 134 ofsemiconductor package 130 in the lid attachment preparation step 70.

Compound 160 may be an adhesive film such as, for example, the thermaladhesive films manufactured by Nitto Denko Corp. of Japan. The compound160 may alternatively be a glue such as, for example, a polyamidehot-melt adhesive like Euremelt® hot-melt adhesives manufactured byHuntsman Corp. of Salt Lake City, Utah. In a further embodiment,compound 160 may be a heat-activated chemical adhesive such as, forexample, a polyurethane-type solvent used in bonding applications.

It is understood that one or more of the embodiments described abovewith respect to FIGS. 6-21 may be combined with each other to affix thelid 138 to semiconductor package 130.

The memory card 140 formed as described above may have any of a varietyof standard card configurations, including for example a Pico card, xDcard, an MMC card, an RS-MMC card, an SD Card, a Compact Flash, a SmartMedia Card, a Mini SD Card, a Transflash memory card or a Memory Stick.Other devices are contemplated.

The foregoing detailed description of the invention has been presentedfor purposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise form disclosed. Manymodifications and variations are possible in light of the aboveteaching. The described embodiments were chosen in order to best explainthe principles of the invention and its practical application to therebyenable others skilled in the art to best utilize the invention invarious embodiments and with various modifications as are suited to theparticular use contemplated. It is intended that the scope of theinvention be defined by the claims appended hereto.

1. A semiconductor package capable of receiving a lid, the semiconductorpackage comprising: an integrated circuit; molding compound forencapsulating the integrated circuit, the molding compound including atop surface and side edges extending at an angle from the top surface,one or more holes formed in the molding compound, the one or more holeshaving a first end open to the top surface of the molding compound and asecond end open to one or more of the side edges of the moldingcompound; and molten material forming a lid for the semiconductorpackage upon hardening, the molten material applied around the moldingcompound, the molten material flowing into the one or more holes, andthe molten material within the one or more holes interlocking the lidonto the molding compound and securing the lid onto the molding compoundupon hardening of the molten material.
 2. A semiconductor package asrecited in claim 1, wherein the one or more holes are formed at anoblique angle through the surface of the molding compound.
 3. Asemiconductor package as recited in claim 1, wherein the one or moreholes are circular.
 4. A semiconductor package as recited in claim 1,wherein the one or more holes comprise a plurality of holes having adiameter of approximately 0.25 millimeters and which are spaced fromeach other approximately 1 millimeter along the edge between the surfaceand the adjacent side edge.
 5. A semiconductor package as recited inclaim 1, wherein the surface of the molding compound includes fouredges, the one or more holes being formed at two of said four edges. 6.A semiconductor package as recited in claim 1, wherein the surface ofthe molding compound includes four edges, the one or more holes beingformed at three of said four edges.
 7. A semiconductor package asrecited in claim 1, wherein the surface of the molding compound includesfour edges, the one or more holes being formed at four of said fouredges.
 8. A flash memory card, comprising: a semiconductor package,including: an integrated circuit, and molding compound for encapsulatingthe integrated circuit, the molding compound including a top surface andside edges extending at an angle from the top surface, one or more holesformed in the molding compound, the one or more holes having a first endopen to the top surface of the molding compound and a second end open toone or more of the side edges of the molding compound; and a lidcovering the semiconductor package, the lid having portions extendingthrough the one or more holes to permanently interlock and secure thelid to the molding compound.
 9. A flash memory card as recited in claim8, wherein the flash memory card is one of a Pico card, xD card, an MMCcard, an RS-MMC card, an SD Card, a Compact Flash, a Smart Media Card, aMini SD Card, a Transflash memory card or a Memory Stick.